Example, Figure 19 - sample phase locked loop configuration – Rockwell Automation 20D PowerFlex 700S AC Drives with Phase II Control Reference Manual User Manual

Page 84

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Rockwell Automation Publication PFLEX-RM003E-EN-E - January 2011

Chapter 1 Detailed Drive Operation

the position reference of the follower drives. Parameter 735 [PLL SpeedOut Adv]
provides a position reference that is advanced by one scan time of the drive’s
control loop. [PLL SpeedOut Adv] should be sent over SynchLink to the
follower drives and linked into the follower drives’ speed reference.

Figure 19 - Sample Phase Locked Loop Configuration

Example:

A “print” retrofit application will replace a mechanical line shaft. The slave drives
will electronically be phase locked to a folder that is controlled by an existing DC
drive. A reference encoder will be mounted to the folder with a 2/3 ratio from the
main line shaft. Rated line shaft speed is 1200 rpm. A multitude of drives of
different ratios are to be electronically geared-off the line shaft.

• Set parameter 147 [FW Functions En], bit 24 “Phase LockLp” = 1 to

enable the Phase Locked Loop function.

To keep things organized, reflect the PLL output to the old line shaft. The slave
units can then reconcile their gear ratio differences with EGR and scale speed
accordingly:

• Set parameter 723 [PLL Rev Input] = 2
• Set parameter 724 [PLL Rev Output] = 3
• Set parameter 727 [PLL VirtEncdrRPM] = 1200

Speed Trim 2

from Encdr0

from Encdr0

Speed Ref 2

Spd Ref2 Multi

from Encdr0

from Encdr0

Local Drive

SynchLink

SL Dir Data

Tx00

SL Dir Data

Tx01

Follower Drive

Phase Locked Loop

Speed Control - Reference

PI

Regulator

300

Motor Spd Fdbk

302

Spd Reg PI Out

Speed Control - Regulator

Motor Speed Ref

301

743

Aux Posit Ref

Gear Rat

[ N ]
[ D ]

PI

Regulator

762

Position Fdbk

Position Control

Linear Ramp

& S Curve

Speed Control - Reference

12

13

*

PI

Regulator

300

Motor Spd Fdbk

302

Spd Reg PI Out

Speed Control - Regulator

Motor Speed Ref

301

+

743

Aux Posit Ref

Gear Rat

[ N ]
[ D ]

PI

Regulator

762

Position Fdbk

Position Control

965

966

929

930

SynchLink

SL Dir Data

Rx01

SL Dir Data

Rx00

22

Speed Trim 2

22

Virtual

Encoder

721

Gear Rat

[ N ]
[ D ]

734

731

735

732

PLL Speed Out

PLL Posit Out

Speed Ref 2

PLLSpeedOut Adv

12

PLL Posit OutAdv

240

13

*

Spd Ref2 Multi

Linear Ramp

& S Curve

Bus Volt
& Power

Regulator

Torq Sel

305

Mtr Trq Curr Ref

Torque Control

Bus Volt
& Power

Regulator

Torq Sel

305

Mtr Trq Curr Ref

Torque Control

318

Posit Spd

Output

318

Posit Spd

Output

728

+

+

Low Pass

Filter

241

Encdr1
Spd Fdbk
(from line
shaft)

Encdr1
Position
(from line
shaft)

PLL Ext Spd Ref

PLL Position Ref

+

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